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<b>DbEnv::mutex_set_tas_spins</b>
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<b><pre>
#include &lt;db_cxx.h&gt;
<p>
int
DbEnv::mutex_set_tas_spins(u_int32_t tas_spins);
<p>
int
DbEnv::mutex_get_tas_spins(u_int32_t *, tas_spinsp);
</pre></b>
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<b>Description: DbEnv::mutex_set_tas_spins</b>
<p>Specify that test-and-set mutexes should spin <b>tas_spins</b> times
without blocking.  The value defaults to 1 on uniprocessor systems and
to 50 times the number of processors on multiprocessor systems.</p>
<p>The database environment's test-and-set spin count may also be configured using the
environment's <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file.  The syntax of the entry in that
file is a single line with the string "set_tas_spins", one or more whitespace
characters, and the number of spins.
Because the <a href="../ref/env/db_config.html#DB_CONFIG">DB_CONFIG</a> file is read when the database environment
is opened, it will silently overrule configuration done before that
time.</p>
<p>The DbEnv::mutex_set_tas_spins method configures operations performed using the specified
<a href="../api_cxx/env_class.html">DbEnv</a> handle, not all operations performed on the underlying
database environment.</p>
<p>The DbEnv::mutex_set_tas_spins method may be called at any time during the life of the
application.</p>
<p>The DbEnv::mutex_set_tas_spins method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</p>
<b>Parameters</b> <br>
 <b>tas_spins</b><ul compact><li>The <b>tas_spins</b> parameter is the number of spins test-and-set
mutexes should execute before blocking.</ul>
<br>
<br><b>Errors</b>
<p>The DbEnv::mutex_set_tas_spins method
may fail and throw
<a href="../api_cxx/except_class.html">DbException</a>,
encapsulating one of the following non-zero errors, or return one of
the following non-zero errors:</p>
<br>
<b>EINVAL</b><ul compact><li>An
invalid flag value or parameter was specified.</ul>
<br>
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<b>Description: DbEnv::mutex_get_tas_spins</b>
<p>The DbEnv::mutex_get_tas_spins method returns the test-and-set spin count.</p>
<p>The DbEnv::mutex_get_tas_spins method may be called at any time during the life of the
application.</p>
<p>The DbEnv::mutex_get_tas_spins method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</p>
<b>Parameters</b> <br>
 <b>tas_spinsp</b><ul compact><li>The DbEnv::mutex_get_tas_spins method returns  the
test-and-set spin count in <b>tas_spinsp</b>.</ul>
<br>
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<br><b>Class</b>
<a href="../api_cxx/env_class.html">DbEnv</a>
<br><b>See Also</b>
<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a>
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